Strengthening the interface between dielectric layers and barrier layers with an oxide layer of varying composition profile

Abstract

A method of processing a substrate including depositing a transition layer and a dielectric layer on a substrate in a processing chamber are provided. The transition layer is deposited from a processing gas including an organosilicon compound and an oxidizing gas. The flow rate of the organosilicon compound is ramped up during the deposition of the transition layer such that the transition layer has a carbon concentration gradient and an oxygen concentration gradient. The transition layer improves the adhesion of the dielectric layer to an underlying barrier layer on the substrate.

1. A method of depositing a dielectric layer, comprising:
 introducing a processing gas comprising an organosilicon compound and an oxidizing gas into a chamber at a first organosilicon compound to oxidizing gas flow rate ratio of at least about 1:40; 
 turning on RF power in the chamber; 
 depositing a transition layer on a substrate in the chamber while ramping up the flow rate of the organosilicon compound into the chamber to provide a second organosilicon compound to oxidizing gas flow rate ratio; and 
 depositing a dielectric layer comprising silicon, oxygen, and carbon on the transition layer for a period of time while maintaining the second organosilicon compound to oxidizing gas flow rate ratio. 
 
   
   
     2. The method of  claim 1 , wherein the organosilicon compound is octamethylcyclotetrasiloxane. 
   
   
     3. The method of  claim 2 , wherein the oxidizing gas is oxygen. 
   
   
     4. The method of  claim 1 , further comprising depositing a barrier layer on the substrate before depositing the transition layer. 
   
   
     5. The method of  claim 1 , wherein the first organosilicon compound to oxidizing gas flow rate ratio is between about 1:40 and about 1:5. 
   
   
     6. The method of  claim 5 , wherein the second organosilicon compound to oxidizing gas flow rate ratio is between about 1:1 and about 3:1. 
   
   
     7. The method of  claim 1 , wherein the first organosilicon compound to oxidizing gas flow rate ratio is about 1:10 and the second organosilicon compound to oxidizing gas flow rate ratio is about 2:1. 
   
   
     8. The method of  claim 1 , wherein the transition layer is deposited under conditions sufficient to provide an oxygen concentration gradient in the transition layer. 
   
   
     9. The method of  claim 8 , wherein the concentration of the oxygen in the transition layer decreases as the layer is deposited. 
   
   
     10. The method of  claim 1 , wherein the transition layer is deposited under conditions sufficient to provide a carbon concentration gradient in the transition layer. 
   
   
     11. The method of  claim 10 , wherein the concentration of the carbon in the transition layer increases as the layer is deposited. 
   
   
     12. A method of depositing a dielectric layer, comprising:
 introducing a processing gas comprising an organosilicon compound and an oxidizing gas into a chamber at a first organosilicon compound to oxidizing gas flow rate ratio of at least about 1:40; 
 turning on RF power in the chamber; 
 depositing a transition layer on a substrate in the chamber while ramping up the flow rate of the organosilicon compound into the chamber at a ramp rate between about 200 mg/min/sec and about 3000 mg/min/sec to provide a second organosilicon compound to oxidizing gas flow rate ratio; and 
 depositing a dielectric layer comprising silicon, oxygen, and carbon on the transition layer for a period of time while maintaining the second organosilicon compound to oxidizing gas flow rate ratio. 
 
   
   
     13. The method of  claim 12 , wherein the organosilicon compound is octamethylcyclotetrasiloxane and the oxidizing gas is oxygen. 
   
   
     14. The method of  claim 12 , wherein the transition layer is deposited under conditions sufficient to provide an oxygen concentration gradient and a carbon concentration gradient in the transition layer. 
   
   
     15. The method of  claim 12 , further comprising depositing a barrier layer on the substrate before depositing the transition layer. 
   
   
     16. A method of depositing a dielectric layer, comprising:
 depositing a barrier layer comprising silicon and carbon on a substrate; 
 introducing a processing gas comprising an organosilicon compound and an oxidizing gas into a chamber at a first organosilicon compound to oxidizing gas flow rate ratio of at least about 1:40; 
 turning on RF power in the chamber; 
 depositing a transition layer on the substrate in the chamber to a thickness between about 80 Å and about 500 Å while ramping up the flow rate of the organosilicon compound into the chamber to provide a second organosilicon compound to oxidizing gas flow rate ratio; and 
 depositing a dielectric layer comprising silicon, oxygen, and carbon on the transition layer for a period of time while maintaining the second organosilicon compound to oxidizing gas flow rate ratio. 
 
   
   
     17. The method of  claim 16 , wherein the barrier layer is a silicon carbide, nitrogen-doped silicon carbide, oxygen-doped silicon carbide, or oxygen and nitrogen-doped silicon carbide layer. 
   
   
     18. The method of  claim 16 , wherein the organosilicon compound is octamethylcyclotetrasiloxane and the oxidizing gas is oxygen. 
   
   
     19. The method of  claim 16 , wherein the transition layer is deposited under conditions sufficient to provide an oxygen concentration gradient in the transition layer, and the concentration of the oxygen in the transition layer decreases as the layer is deposited. 
   
   
     20. The method of  claim 19 , wherein ramping up the flow rate of the organosilicon compound into the chamber to provide a second organosilicon compound to oxidizing gas flow rate ratio comprises a ramp rate between about 200 mg/min/sec and about 3000 mg/min/sec.